Writing instrument



Sept. 2s, 1954 R. W. RAN DOLPH WRITING INSTRUMENT 2 Sheets-Sheet l Filed Oct. 3, 1951 mmwmmw @liv Nm, m.

INVENTOR.

2 Sheets-Sheet 2 R. W. RANDOLPH WRITING INSTRUMENT QQ QN QN NN WN #Mv/VvV/wvvvVJvydwVvVVVV// Sept. 28, 1954 Filed Oct. 3, 1951 QN QN QN. N NQ QW. QQ QA Patented Sept. 28, 1954 The Parker Pen Company, JanesvillawWviapa corporation of Wisconsin f f Y' Application October 3, 1951, Serial No. 9.319,503 v Y lThis invention relates generally to writing instruments and has to do particularly with a writing instrument of the type including afcasing in which kis mounted awriting point adapted to be projected from the casing into a writing posi tion or retracted into a concealed and protected position Within the casing.

One of the objects of my invention is to provide an improved writing instrument of the foregoing character.

instrument of the foregoing character having a casing'with'extensible vand contractible casing sectionswhich can be telescoped over one another so that the instrument when contracted is of minimum length for insertion in ones pocket, and 'when the sections are extended,v the instrument is of convenient vlength for holding in the hand for writing purposes, and in'which the writing point is projected from the casingby manipulation of the casing sections afterthe latterV are' moved to' extended position.

I A further object of the'invention is the provision of a writing instrument of the character referred to in which the writing pointis automatically locked` in Writing position "when manipulated to effect the projecting movement thereof so that it cannot be vretracted int'ofthe casing by pressure applied to the point in a writing operation.

`rStill another'object is the provision of awriting instrument of the character referred to in which the writing point can be projected out of the casing only after the casing sections have been extended, whereby the point is not likelyto be projected accidentally.

f :Sitill'1 another object is the provision of a writing instrument of the character referred to'in which the writing point must be completely retracted into the casing before the manipulation effecting the contracting movement `of the casing sections can be accomplished, thereby minimizing the likelihood of inserting the instrument in a pocket with the Writing point projected, with consequent elimination of the probability of soiling the clothes of the user such as may occur if the'instrurnent is inserted in the pocket with the writing point projected.

A further object is the provision of a writing instrument of the character referred to in which there is minimum resistance to extension and contraction of the casing sections.

A 4still further object is the provision of a writing instrument having a casing and a writing unitinludne 'e Writing peint for projecten fram 1o claims. (c1. 1to1-42.03)v

Another object is the provision of a writing Y ment vin extended condition;

Fig.' 3 is'anenlarged, longitudinal' sectional view the casing, in whichthe casing' includes separable parts for exposing the interior of the casing 'and thereby facilitating insertion'of the'unit inthe casing and removal therefrom, and in whichl means is provided for vfrictionally retainingthe unit in the casing under normal conditionsbut permitting the unit to be removed in to force applied for that purpose;

Another object is the provision of' a writing instrument ofthe foregoing character of exceedingly' simple "construction, and containing a minimum number of parts.

Otherv objects WiIlappear from the following' description in conjunction with theaccompanyr ing drawings, in which:

Figure 1 is a side elevational view of the writing instrument of the presentinventionin contracted condition; I v Fig. 2 is a side elevational 'view of the' instruo f the instrument in contracted condition;

Fig.'4is"a 'sectional view taken on line 4-"4 of Fig. 3; l y

Fig. 5 is a sectional view taken on staggered' Fig. 6 is a'sectionalview taken'on line 6 5:

ofFig. 3;

Fig. '7 is a longitudinal view ofthe instrument'l showing certain outer portions in section and certain inner portions in elevation, with the instrument in contractedV position, the viewbeing taken at right angles With'respect'to the view of Fig. 3;

Fig. 8 is a'view" similar to Fig; 7 but with the instrument in extended position,v before relative rotation of the 'casing sections has taken place and with the Writing point retracted Vinto the casing; and

Fig. 9 is a view-'similar tot Fig. s but after relative rotation of the casing 'sections has taken place and with thewriting point projectedj'frorn the casing. y

The Vpresent invention' is particularly well adapted to a ball point' writing instrument', and:

Referringin detail 'to the drawings mainstrement as a whole is s'hoWnat l2 in Figs. land 2,"

Fig. 1 showing'xthe. instrument-,in contracted positien @neef reduced, leveren, that it caribe response veniently placed in a pocket or in a purse. In Fig. 2 the instrument is illustrated in extended position for writing, and as observed in the two figures in extended position the instrument is of substantially greater length than when contracted. Also it will be observed that when the instrumentfisin contracted positionliig. 1) the Writing point is retratedinto thepen casing soA that the writing point will not soil the clothes of the user when inserted in the pocket, as men-,

tioned above. The writing point is of course projected for writing purposes, as illustrated in Fig. 2, being projected by relative movementv of. the

v relative'to the body sleeve 30 as well as the nose portions of the instrumentnassociated;with the I operation of extending the instrument.

The casing of the nstrumentismade up o f al forward casing section I4 and-1a rear casing section I6, the two sections being associated for sliding telescopic movement relative to one another infa longitudinaltdirection. The rear casing section substantially# encloses the `forWardcasing section When the instrument is inscontracted position whereby theinstrument isof minimum length when contracted.

The two casing sections` 1,4 andl |65 together form a casingfor containing a writing unit, indicated in its entirety at IIL'Which may be of any suitable type. Briefly, the writing unit l8 includes a reservoir element ,20 of cylindrical shape.

providing anink reservoir, a writing point 22 having a ball 24 mounted inits writingtip, and a feed 26` for feeding thewritinggfluid from the reservoir 2,0,to the Writing point. Therreservoir element may be detachable from the feed 26 for replacement whenptrhe ink'lis exhausted.

The forward casingA section I4 takes the form4 of an assembly including a nose member` 2,8, a body sleeve 30 and a.. slide sleeve or cover sleeve 32. The exterior surface of the. nose member 28 tapers to a writing endof substantially .reduced diameter, andis ofrelativelyhe'avy andrugged Wall constructiomas shown for examplein Fig. 3. The nose member 28 includes a small` diameter, opening Ior bore,34\ at` its forward,writingVv end,

of such diameter as to freely receive `thefeed 24,6T for projection of the writing point 22 therethrough so that the ball 24 is exposed forlwriting purposesas illustrated in Fig. 2. Rearwardly of the small diameter bore 34` is an enlargedbore 3 6 for accommodating: the forward endl of the reservoir element: 20 when lthe writing unit is moved forwardly therein in the movement ofy projectingA the` writing point through-` the bore 34. The rear end oflthe nose member 28`is of slightly reduced external diameter and provided with external threadsl 38 for-receiving the internal threads 40 at the forward end ofz'thebody sleeve 30, for rigidlyconnecting the nose member and body sleeve together.

The nosemember 28 and body sleeve 30` form the body of the instrument, supportingI the rear casing section and the writing unit. rI he body sleeve 30 maybe imperforate throughout its extent except for, an aperture 42Aadjacent itsrear end into which is inserted a pin 4,4` extending radially inwardlyfromthe sleeve for extending into certain slotswin Yother portions o f the pen, as will be referred to in 'detail latenter aiding in guiding the casing` sections and for: aidingM in moving the writing unit for projection and retraction of the Writing pointthrough' the opening 34 in the nose member 28.`

A11Y v0f the Qperatinemechanism of. the instru.- mentis concealedby portionsof the ca singsections as Awill be apparent as the description member 28,-. `rfhecover sleeve 32 is also effective for: retaining. thepin 44 in place in the aperture e 4,2,.t`hegpinif` desired being otherwise removable outwardly from the aperture 42 so as to facilitate assembly and disassembly of the pen. Thus the cover sleeve covers the body sleeve and imparts a finished appearance to'that portion of the instrument. 2md- Qonceals the. pin 4.4,which-c0nstitutesan element of theoperating mechanism of the instrument.,v

The,threads.3,8 andAll enable d etachmentof the nose member 2 8: fromthebodylsleeve 3Q and from the slide sleeve 32 tov enable the writing,

unit to be inserted in and removed from. the ciegas is necessary upon ,exhaustionoi the, supply of writing fiuid in the reservoir. Such Aremoval and replacement can be made with facility upon removal of the .nose .member 28 .merely by'. holding the instrument in o neglriandand.'P grasping, the

writing unit inthe other hand and pulling it out` 0f thecasing.

The reservoir element 2 0is.frietionally, tted in and carried by aspiralsleeve or driven sleeve 50, the latter directly engaging the. innerV surface of one of theelernentsmakingupthe rear easing I6J` as` will e be referredy to later. i The.

driven sleeve 50 atanyQconvenient location therein such as adjacent theforward end (Fig. 3) is provided with a pluralitye. g., four) of RmgigY tudinal slotsl5x2 spaedcircumferentiallyA o f the sleeve and preferably arranged in pairs, the.l two slots of each pair (one. pairshow n in Fig. 3)

dening` therebetween, a; strip lEtwhch is bentA or depressed.. radially inward-ly forforming a friction `gripping area engageable with Vthex-V These` terior sur-faceof, theneservoirl element'. areas 54, one on each of opposite sides of the driven sleeve by frictiona lly` engagingI the reservoir element, normally. retainit in place in the sleevebut permit. removal ,of the writing unit upon applicationof` sufcient' pressure for that` purpose, such ausi by,l withdrawing by the hand.

In thenornialpperation. of the instrument the writing unitJB andrthedriven sleeve 56 lmove together as a. single unit. in the projecting. and retractingI movements lof the writing l unit.,4 Therefore the writing, unitl and t driven. sleeve together form, ineffect, azsingle: unit so far. as concerns the projection.andretracticn of thepoint. l The driven sleeve .5G vandthe writing unit arearranged for conjoint longitu dinalsliding` movement with respectto the instrument as va wholefor producing projecting andV retractingl movements, e while they also rotate relative tooneof thecaxsing sections, as willbeexplanedindetailtlater. A novel arrangement of, cam means is providedfor, producingv the. projecting and, retracting. movement of the writing unit raslwill be explained fully in a later partv of the description.`l

The Spiral. 01 driven Sleeve, isprovidedwith a helicalY or sot-called spiral slot 55 Hextending* oircumferentially of the sleeve slightly more than 180 so that a full 180 of relative rotational movement between the casing sections is permitted, consideration being given to the thickness of the cam means working in the slot which is consti- .tuted by the pin 44 which may also be referred to viewed from the writing point end of the instru-v ment. The slot is shown in Fig. 5 which is a view on staggered line 5--5 of Fig. 3, following the inclination of the slot, the shape of the slot being shown to better effect in Figs. 7-9. In Fig. 3 only the ends of the slot are indicated, the remaining portion being in that portion of the sleeve removed from the ligure.

The driven sleeve 50 is also provided with a radially outwardly extending projection 58 which may be formed integrally with the sleeve by any appropriate shaping operation. This 'projection 58 is in effect a pin and also forms a cam element, extending into a slot 82 formed in one of the elements of the rear casing section as will be referred to later. The projection 58 is positioned adjacent the rear end of the driven sleeve, and as here shown is at least as far rearward as the rear end of the spiral slot 56. In the contracted position of the instrument the projection 58 is disposed rearwardly of the pin 44.

The rear casing section I6 is provided with elements for cooperating with other elements in the forward casing section for moving the writing unit in projecting and retracting directions, and also is provided with a sleeve for telescoping over and concealing the greater portion of the forward casing section when the instrument is in contracted position. The rear casing section I6 is made up of an inner sleeve or drive sleeve 60 and an outer sleeve 62 secured together by connecting means which will be described at this point so that uninterrupted attention can later be given to the main elements of the instrument. The sleeves 60 and 62 are provided with inturned flanges 64 and 66 respectively at their rear ends, tted together and resting on a shoulder 68 formed on an annular plug l0 having interior threads for threadedly receiving a screw bushing l2 having both exterior and interior threads. The outer end of the screw bushing 'I2 diverges rearwardly forming an exterior surface 13 for engagement with a sleeve ring 74, the latter having one end engaging the ange 86 and provided at its other end with a tapered-surface opening 16 complemental in shape to and engaged by the surface 13. The outer end of the screw bushing 'l2 is provided with a kerf 'I8 for use in threading the bushing into the plug 10. Upon being threaded down, the screw bushing acting through the cap element 'i4 effectively secures the sleeves 60 and 62 together and with the plug 10. Finally a screw 80 is threaded into the interior threads of the bushing 'l2 for poviding a finished appearance to the rear end of the rear casingsection.

The drive sleeve '60 of the rear casing section cooperates with the forward casing section in the extension and contraction movements of the casing sections for projecting and retracting the writing point through the opening 34 of the nose member 28. This sleeve is so shaped as to t snugly in the body sleeve 38 but with freedom for sliding and rotational movement therein. The sleeve 60 is provided with a slot82 for producing certain camming effects 'as will be referred to later, and forguiding the. casing-sections in their expanding and contracting movements, the slot having a longitudinal portion 84 anda circumferential portion 86 at the forward end of the longitudinal portion. The longitudinal portion 84 of the slot extends from a point adjacent the rear end of the sleeve to a point closely adjacent the forward end thereof where the circumferential portion 86 of the slot communicates with the longitudinal portion and continues around the sleeve in a plane perpendicular to the longitudinal axis of the instrument for slightly more than to accommodate relative rotation of the casing sections a full 180 in the manner referred to in connection with the spiral slot 56. In the assembled instrument, the circumferential portion 86 of the slot 82 is disposed on the same side of the instrument as is the spiral slot 56. The longitudinal portion 84 of the slot extends parallel with the axis of the instrument so that in the extending movement of the casing sections they are extended directly longitudinally without rotation. The pin 44 secured in the body sleeve 30 extends through the longitudinal portion of the slot 82 when the casing sections are contracted (Fig. 3) but when the casing sections are extended (Fig. '8), the pin 44 is in position for moving into the circumferential portion 88 of the slot in response to relative rotation of the casing sections. The projection 58 also extends into the longitudinal portion of the slot 82 but as will be referred to later, it does not move into the circumferential portion of the slot.

The drive sleeve 6l) receives the driven sleeve 50 in engagement with its inner surface and the two sleeves are fitted for free relative sliding movement although there is no relative rotational movement between the drive sleeve 60 and the driven sleeve 50.

When the instrument is contracted, the outer sleeve 62 encases all of the other sleeves, and it will be evident that it conceals all of the operating mechanism. When thel instrument is extended all of the operating mechanism is concealed by the outer sleeve 62 and the cover sleeve 32. The two sleeves 62 and 32 therefore conceal all of the operating mechanism and provide a iinished appearance to the instrument.

When the instrument is in contracted position (Figs. 3 and 7) it will be noted that the writing point 22 is retracted through the bore 34 into the casing. Also it will be noted that the pins or projections 44 and 58 are both adjacent the rear end of the longitudinal portion 84 of the slot 82. These projections are spaced apart a distance at least as great as the extent of movement of the writing unit in the -projecting and retracting movements of the latter.

To extend the instrument and project the writing point, the first stepis to grasp the casing sections and pull them in extending direction. This results in relative longitudinal movement of the sections without relative rotational movement since the pin 44 is fixed in the sleeve 88 and rides in the longitudinal portion 84 of the slot 82. The extending movement is limited by the pin 44 engaging the forward end of the longitudinal portion 84 of the slot 82. The writing unit in the extending movement just referred to does not move relatively to the forward casing section, being restrained by the pin 4-4 engaging the spiral slot 56 and since .the spiral or driven sleeve 50 and the writing unit are restrained against rotational movement by the projection 58 in the longitudinal portion 84 of the slot 82, the writing .unit .remains .stationary relatively. to. the.

encodes.

forward casing section. The only movement thus permitted in the initial portion-of extending and projecting operation is rearward movement of the rear casing section relative to the forward casing section.

The `position of the parts after the extending movement as above referred to is shown in Fig. 8 where the pin im is at the forward end of the portion Sil of 4the slot -82 and in position to move into the portion 8@ of the slot. In this position of the parts also the projection A58 is near the forward end of the vportieri 84 of the slot, but spaced rearwardly therefrom the same distance as the spacing thereof when the sections are -contracted (Figs. 3 and 7).

With the parts in extended position as just referred to and as shown in Fig, 8,. .and for the purpose of projecting the writing point, the rear casing section is rotated relatively to the forward casing section in a right-hand screw threading motion, i. e., it is rotated clockwise as viewed from the rear of the instrument. r'he pin lid thus rides into the circumferential Aportion Et of the slot 82. The pin 'All it will be recalled also extends into the spiral slot 56 and because `of the. relative rotational movement between the casing sections, the pin iti rides in the spiral slot, and since the driven sleeve d is prevented from rotating by the engagement lof the projection 53 in the longitudinal portion 84 in the slot B2, the effect is a camming .action between the pin i4 and the spiral slot 5t, moving the :driven sleeve Ei@ and the writing unit forwardly of the casing for projecting the writing point 'through the bore 3&3. The projecting movement of the writing Lmit results in a component of longitudinal movement thereof during which the projection 58 continues to ride in the longitudinal portion 84 of the slot 82 to a position approaching the forward end thereof as shownin Fig. 9. Thesame eiect can be procured by -placing the projection 53 rearwardly of the position shown so that .the spacing between it andthe pin in is greater than the longitudinal component of dimension of the spiral slot, the consideration being that projection 5B is placed rearwardlyV sufficiently that it is not limited in its relativeforward movement by the forward end of the portion .S4 of .the slot 82,

Thus the slot 5t constitutes a cam element having both longitudinal and circumferential components, the pin i4 xed in the body sleeve St constitutes a cam element having a longitudinal component, andthe projection 58 and the longitudinal portion 84 of the slot 82 together constitute a cam .element having a. circumferential component.

When the writing unit is in projected position as described and as illustrated in Fig. 9, the writing unit is locked against retraction by any force applied longitudinally to the writing point and therefore the pressure applied tothe writing point in writing, regardless of its force, will not retract the writing unit into the pen casing. The i'orce applied longitudinally to the writing point as in writing is resisted by the pin Mi which is fixed in the body sleeve, and by the edge .ofthe portion 84 of the. slotin cooperation with the pro.- jection 58. The pin :idrestrains the writing unit from longitudinal movement and the portion 84 of the slot cooperating with the projection 58 restrains the writing unit from relative -rotationbetween the writingunit and the rear .casing section. In orderffor the writingY unit to beretracted it must berotated in order to enable the pin i4 to ride in the. .spi-ral `slot, 5B and since it is held againstr rotation, it is restrained against retraction by the-.force .applied as mentioned when the casingsections vare Yexpanded and relatively rotated. rIfhe writing point can be retracted only by relatively rotating the casing sections in the reversedirection from that employed in projecting the Writing point, namely, by rotating the. rear `casing. section relatively to the forward casing tsection by a left-.hand screw threading motion (as` viewed `from .the rear of the instrument). This :relative rmotion places the pin or projection 44 .in -or inline with the longitudinal portion of lthe slot 82. Thereafter the casing sections may be contracted bytelescopically yrnoving them together in .a longitudinal direction. The casing sections cannot be contracted when the writing ypoint is projected. The sections must rst be 'rotated for yretracting the writing point, after which they can r'be contracted.

It will be evident from the foregoing that the probability of vinserting the instrument in the pocket while the Writing point is projected, is virtually eliminated. -It is desirable of course that suchY .occurrence be avoided so that the clothes of the luser will not be soiled. At no time when the `casing sections are fully retracted or only ,partially'retractedgcan the writing point be projected. The writing point can be projected only after the casing ysections are fully extended and rotated relatively to .one another. Thus, if the instrument while .fin the pocket should become ,partiallyzextended the writing point would not 'be projected Yso as -to soil the clothes, and it is virtuallyimpossible. for the casing sections to be extended :and `rotated by accident when in the zpocket.

I claim:

l. In awritinginstrument, a casing including a forwardsection'and a rearsection, the forward section having anropening at its forward writing end, |and the yrear section being telescopically slidable onv the yforward section, a writing unit having -a v.writing-point and mounted in the casingl forv longitudinal sliding movement therein for projection and Vretraction of the writing point through said opening, and-means interconnecting said sections and unit operative for moving the unit and projecting the writing point in response to Vrelativemovement between the sections, said meansincluding an inclined cam element on said writing -unit adjacent -the rear end thereof, a cam element on one of `the sections having a straight longitudinal portion and a circumferential portionadjacent one end thereof lying substantially in a plane perpendicular to the longitudinal axis of the section, and a cam element on'the other'section engageable with said first two ycam elements, said last cam element and circumferentialportionjbeing relatively positioned for interengagement Vonly when the casing sections are extended.

2. In Aa writing instrument composed of three main partsincluding a forward and a rear casing section `and a writing unit, the casing sections forming a casing containing the unit, the forward casingY section having an opening at its forward writing. end, and the rear casing section being.y telescoplcally slidable on the forward section, for longitudinal extensionand contraction of 'the sections, the unit having a writing point and .beingmounted inthe .casing for longitudinal sliding-movementtherein for projection and retraction of-thewriting point through said opening, and cam means interconnecting the three parts comprising a first cam element on one of the parts having a longitudinal and a circumferential component, a second cam element on another of the parts having a longitudinal portion of substantial length and a circumferential portion at one end of the part, and a third cam element on the third part engageable with the first and second cam elements, said cam means being relatively positioned as to be operative for retaining said sections against relative rotational movement in the extension and contraction movements thereof, and enabling relative rotational movement of the sections only when in extended position and retaining the sections against relative longitudinal movement when extended and relatively rotated, and operative for moving the unit and projecting the writing point in response to relative rotation of the section when in extended position.

3. In a writing instrument, a casing including a forward section having an opening in its forward writing end, and a rear section telescopically slidable on the forward section for extension and contraction of ther sections, a writing unit having a writing point and slidably mounted in the casing for projection of the point outwardly through said opening and retraction inwardly therethrough, one of said sections having a slot with a longitudinal portion and a circumferential portion at one end thereof, said unit having a spiral slot, the other section having a projection extending` into both of said slots, said projection being positioned relative to said other section for positioning in said longitudinal portion when the sections are contracted and for positioning in said circumferential portion only when the sections are extended, said unit having a projection extending into said longitudinal slot portion on the side of the first projection opposite said circumferential slot portion, whereby the casing sections are extendible longitudinally after which relative rotation of the sections moves said unit for projection of its writing point through said opening.

4. In a writing instrument, a casing including a forward section having an opening in its forward writing end, and a rear section telescopically slidable on the forward section, a unit having a writing point slidable in the casing for projection of the point outwardly through said opening and retraction inwardly therethrough, said rear section having a slot including a longitudinal portion and a circumferential portion at the forward end of the longitudinal portion, said unit having a spiral slot adjacent its rear end, said forward section having a projection extending into both of said slots, and said unit having a second projection extending into the slot in said rear section rearwardly of said rst projection, said sections being thereby extendible with both of said projections riding in said longitudinal portion of the slot, whereafter upon relative rotation of the sections said first projection rides in said circumferential portion of the slot and in said spiral slot and Said second projection remains in said longitudinal portion of the slot in the rear section and retains said unit against rotation relative to said rear section.

5. In a writing instrument, a casing including a forward section and a rear section telescopically slidable on the forward section, said forward section including a nose member having an opening at its forward writing end, and a body sleeve detachably connected to said nose member and extending rearwardly therefrom, said rear section including a drive sleeve telescopically slidable in said body sleeve, a writing unit encased generally in said body sleeve for sliding movement therein and having a writing point positioned for projection and retraction through said opening in response to movement of the unit, said drive sleeve having a slot including a longitudinal portion and a circumferential portion at the forward end of the longitudinal portion, said unit having a spiral slot adjacent its rear end, said body sleeve having a fixed projection adjacent its rear end extending into and relatively slidable in both of said slots, and said unit having a fixed projection extending into and relatively slidable in said longitudinal portion of the slot in the drive sleeve rearwardly of said first projection.

6. In a writing instrument, a casing including a forward section and a rear section telescopically slidable on the forward section, said forward section including a nose member having an opening at its forward writing end, and a body sleeve `detachably connected to said nose member and extending rearwardly therefrom, said rear section including a drive sleeve telescopically slidable rin said body sleeve and having a slot with a straight longitudinal portion and a circumferential portion adjacent one end of the longitudinal portion, a driven sleeve havingy a spiral slot and slidably disposed in said drive sleeve, a writing vunit having a writing point and frictionally held in said driven sleeve for movement therewith for projection and retraction of the writing point through said opening, said body sleeve having a fixed pin adjacent its rear end extendinginto both of said slots, and said driven sleeve havingA a -xed pin extending into said longitudinal portion of the slot in the drive sleeve rearwardly of said first xed pin.

7. In a writing instrument, a casing including a forward section and a rear section telescopically slidable on the forward section, said forward section including a nose member having an opening at its forward writing end, a body sleeve detachably secured to said nose member and extending rearwardly therefrom, a cover sleeve detachably tted on said body sleeve and having a portion detachably secured between said nose member and body sleeve, said rear section including a drive sleeve telescopically slidable in said body sleeve with a slot having a longitudinal portion and a circumferential portion at the forward end thereof, a driven sleeve having a spiral slot slidably disposed in said drive sleeve, a writing unit having a writing point and frictionally held in said driven sleeve for movement therewith for projection and retraction of the writing point through said opening, said body sleeve having a fixed projection adjacent its rear end extending into both of said slots, and said driven sleeve having a fixed projection extending into said longitudinal portion of the slot in the drive sleeve rearwardly of said rst fixed projection.

8. In a writing instrument, a casing including a forward section and a rear section telescopically slidable on the forward section, said forward section including a nose member having an opening at its forward writing end, a body sleeve detachably secured to said nose member and extending rearwardly therefrom, a cover sleeve detachably fitted on said body sleeve and having a portion detachably secured between said nose member and body sleeve, said rear section includend thereof, the outer sleeve 'being telescopieally slida-ble over said cover sleeve, a driven sleeve having a spiral slot and' slidably disposd in said drive sleeve, a writing unit having a writing point and frictionally held in saiddriven sleeve and movable therewith for projection and retraction of the writing point through said opening, said body sleeve having a fixed `projection adjacent its rear end extending into both of said slots, and said driven sleeve having va fixed projection extending into said longitudinal portion of the slot in the drive sleeve rearwardly of said rst fixed projection.

9. In a writing instrument, a casing including a forward section and a rears'ection telescopically slidable on the forward section, said forward section including a nose member having a reduced dimension opening at its forward writing end, a body sleeve detachably secured to said nose member and extending rearwardly therefrom, said rear section includ-ing a drive sleeve telescopically slidable in said body sleeve, said instrument also including a generally cylindrical driven sleeve having a spiral slot and slidably disposed in'said drive sleeve, a writing unit having a relativelysmall forwardly extending writing point and a relatively large rear cylindrical portion fitted in said driven, sleeve, the forward end of said body sleeve being of at least as great dimension as said cylindrical portion. and the driven sleeve having a plurality of slots with inwardly bent portions between adjacentv slots in engagement with said writing unit for frictionally but removably retaining the writing unit y12 in the driven sleeve, and the writing unit being thereby movable with said driven sleeve for projection and retraction of the writing point through said opening, and cam means on said Ycasing sections and driven sleeve effective for moving the driven sleeve for projection and retraction of the writing point in response to relative movement between the casing sections.

l0. In a writing instrument, a casing including aforward section and a rear 'section telescopically slidable relative to each other, said forward section including a nose member of substantial thickness and having a small diameter bore at its forward writing end and a larger diameter bore adjacent its rear end, and a shell-like body sleeve detachably connected to the rear end of said nose member and extending rearwardly therefrom, said rear section including a shelllike drive sleeve sldable in said body sleeve and having a slot with a longitudinal portion and a circumferential portion at the forward end of the longitudinal portion, a writing unit having a writing point and slidably disposed in said drive sleeve for projection and retraction of its point through said small diameter bore, said writing unit lhaving a spiral slot adjacent its rear end, said body sleeve having a projection adjacent its rear end extending into both of said slots, and said unit having a projection extending into said I-longitudinal portion of the slot in the drive sleeve rearwardly of said first projection.

` References Cited in the file of this .patent UNITED STATES PATENTS Number Name Date 544,533, Harpfer Aug. 13, 1895 940,247 Haring Nov. I6, 1909 

